1. Field of Invention
The invention relates to an antenna and, in particular, to a dual-band inverted-F antenna.
2. Related Art
The rapidly developed radio transmission has brought various products and technologies applied in the field of multi-band transmission, such that many new products have the performance of radio transmission to meet the consumer's requirement. The antenna is an important element for transmitting and receiving electromagnetic wave energy in the radio transmission system. If the antenna is lost, the radio transmission system cannot transmit and receive data. Thus, the antenna plays an indispensable role in the radio transmission system.
Selecting a proper antenna can match the feature of the product, enhance the transmission property, and further reduce the product cost. Different methods and different materials for manufacturing the antennas are used in different application products. In addition, considerations have to be taken when the antenna is designed according to different frequency bands used in different countries.
As shown in FIG. 1, a conventional antenna 1 has a first radiating unit 11 and a second radiating unit 12. The first radiating unit 11 has a long side 111 and a short side 112. The second radiating unit 12 has a first radiating part 121, a second radiating part 122, and a third radiating part 123. The second radiating part 122 and the third radiating part 123 are respectively extended from one side of the first radiating part 121. There is a gap 13 between the first radiating part 121 and the first radiating unit 11.
Generally speaking, the operating band of the antenna 1 ranges from 5.15 GHz to 5.25 GHz. With the technical advances, the band defined by IEEE 802.11a ranges between 4.9 GHz and 5.85 GHz. It is seen that the antenna 1 cannot satisfy current needs. Moreover, most modern antennas have the functions of dual or multiple operating bands to enhance their performance and applications.
Therefore, it is an important subject of the invention to provide an antenna with a larger operating bandwidth suitable for modern needs and having dual bands.